This is a weird take. Rust is very popular and is the current heir apparent to C for systems level stuff. It's a great choice to start a new DE/toolkit.
As for the rest, you're right the end user doesn't care about the language their graphical app is in, but the developers fielding their bug reports and making fixes/features sure do.
TIOBE is weighted toward languages that have existed for a long time by virtue of counting lines written / skilled engineers etc. but the speed at which Rust is climbing that list is a better indicator. Also, a lot of the languages above it wouldn't be appropriate for anything like a DE.
But you're right, it's hyped, I just think the hype is real.